JPH0762147B2 - Synthetic lubricant - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a novel synthetic lubricating oil, and more specifically to a naphthyl ether compound or a naphthol ester compound having a certain structure as a main component, which has high oxidative stability. Particularly, the present invention relates to a novel synthetic lubricating oil.

[Prior Art] Lubricants are generally required to withstand long-term use. Therefore, a highly refined mineral oil, which is blended with an appropriate antioxidant if necessary, is usually used as a lubricating oil. However, mineral oil has a limited oxidative stability, and it is difficult to use it for a long period of time in an environment with severe temperature conditions. Therefore, ester-based synthetic oils such as diesters and polyol esters and hydrocarbon synthetic oils such as poly α-olefins have been developed and are now widely used as lubricating oils having more excellent oxidation stability.

However, although these conventionally known synthetic lubricating oils are said to have higher oxidative stability than mineral oils, their oxidative stability was not satisfactory.

[Problems to be Solved by the Invention] In order to solve such a problem, an object of the present invention is to provide a novel synthetic lubricating oil which is particularly excellent in oxidation stability and can be stably used for a long period of time.

[Means for Solving the Problems] As a result of repeated research to develop a synthetic lubricating oil that can achieve the above objects, the present inventor has at least a naphthyl ether compound or a naphthol ester compound having a certain structure as a main component. The present inventors have found that synthetic lubricating oils have markedly higher oxidation stability than known synthetic lubricating oils, and have completed the present invention.

That is, the present invention provides a naphthyl ether compound represented by the following general formula (I) [In the formula, X ₁ represents an alkyl group having 1 to 20 carbon atoms, a phenyl group,
C7-C26 monoalkylphenyl group or general formula And (or R ₁ represents an alkylene group having 2 to 20 carbon atoms)] and / or a naphthol ester compound represented by the following general formula (II) [In the formula, X ₂ is an alkyl group having 1 to 20 carbon atoms, or A group represented by the formula (R ₂ represents an alkylene group having 1 to 20 carbon atoms, n represents a number of 0 or 1)] as a main component. It is a thing.

Hereinafter, the content of the present invention will be described in more detail.

The naphthyl ether compound used in the synthetic lubricating oil of the present invention has the general formula The α-substituted compound represented by The β-substituted product can be used, but the α-substituted product is preferably used from the viewpoint of physical properties as a lubricating oil and the availability of raw materials.

The group represented by X ₁ has 1 to 20 carbon atoms, preferably 4 carbon atoms.
~ 18 alkyl group, phenyl group, C7-26, preferably 7-24 monoalkylphenyl group, or general formula It is necessary that it is a group represented by (R ₁ represents an alkylene group having 2 to 20 carbon atoms, preferably 4 to 16 carbon atoms). Use of a naphthyl ether compound that does not satisfy the above numerical values is not preferable because it is inferior in oxidation stability and physical properties as a lubricating oil as compared with the naphthyl ether compound used in the present invention.

Moreover, among these groups represented by X ₁ , the alkylphenyl group needs to be a monoalkylphenyl group. It is not preferable to use a naphthyl ether compound having a polysubstituted alkylphenyl group because it is inferior in oxidation stability and physical properties as a lubricating oil. The monoalkylphenyl group is preferably an ortho-substituted product in terms of oxidation stability and physical properties as a lubricating oil, but a meta-substituted product or a para-substituted product can also be used.

Also, the general formula The group represented by The α-substituted compound represented by The β-substituted product can be used, but the α-substituted product is preferably used from the viewpoints of physical properties as a lubricating oil, availability of raw materials, and the like.

The naphthol ester compound used in the synthetic lubricating oil of the present invention has a general formula The α-substituted compound represented by Can be used in the β-substituted form, but in terms of physical properties as a lubricating oil, availability of raw materials, etc., α-
Substitutes are preferably used.

The group represented by X ₂ has 1 to 20 carbon atoms, preferably 4 carbon atoms.
~ 18 alkyl groups, or general formula (R ₂ represents an alkylene group having 1 to 20 carbon atoms, preferably 4 to 16 carbon atoms, and n represents a number of 0 or 1). Use of a naphthol ester compound that does not satisfy the above numerical values is not preferable because it is inferior in oxidation stability and physical properties as a lubricating oil as compared with the naphthol ester compound used in the present invention.

In addition, among these groups represented by X ₂ , a general formula The group represented by The α-substituted compound represented by Can be used in the β-substituted form, but in terms of physical properties as a lubricating oil, availability of raw materials, etc., α-
Substitutes are preferably used.

Further, among the groups represented by X ₁ , an alkyl group, an alkyl group of an alkylphenyl group, an alkyl group among the groups represented by X ₂ , and an alkylene group represented by R ₁ and R ₂ are directly Both chain-like and branched ones can be used.

In the synthetic lubricating oil of the present invention, among the groups represented by X ₁ of the naphthyl ether compound, an alkyl group, an alkyl group of an alkylphenyl group, and a naphthol ester compound
Preferred examples of the alkyl group among the groups represented by X ₂ include, for example, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group,
Undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, se
c-butyl group, 1-methylbutyl group, 1-ethylpropyl group, 1-methylpentyl group, 1-ethylbutyl group, 1
-Methylhexyl group, 1-ethylpentyl group, 1-propylbutyl group, 1-methylheptyl group, 1-ethylhexyl group, 1-propylpentyl group, 1-methyloctyl group, 1-ethylheptyl group, 1-propylhexyl group Base,
1-butylpentyl group, 1-methylnonyl group, 1-ethyloctyl group, 1-propylheptyl group, 1-butylhexyl group, 1-methyldecyl group, 1-ethylnonyl group,
1-propyloctyl group, 1-butylheptyl group, 1-
Pentylhexyl group, 1-methylundecyl group, 1-ethyldecyl group, 1-propylnonyl group, 1-butyloctyl group, 1-pentylheptyl group, 1-methyldodecyl group, 1-ethylundecyl group, 1-propyl Decyl group,
1-butylnonyl group, 1-pentyloctyl group, 1-hexylheptyl group, 1-methyltridecyl group, 1-ethyldodecyl group, 1-propylundecyl group, 1-butyldecyl group, 1-pentylnonyl group, 1- Hexyloctyl group, 1-methyltetradecyl group, 1-ethyltridecyl group, 1-propyldodecyl group, 1-butylundecyl group, 1-pentyldecyl group, 1-hexylnonyl group, 1
-Heptyloctyl group, 1-methylpentadecyl group, 1
-Ethyltetradecyl group, 1-propyltridecyl group,
1-butyldodecyl group, 1-pentylundecyl group, 1
-Hexyldecyl group, 1-heptylnonyl group, 1-methylhexadecyl group, 1-ethylpentadecyl group, 1-propyltetradecyl group, 1-butyltridecyl group, 1-
Pentyldodecyl group, 1-hexylundecyl group, 1-
Heptyldecyl group, 1-octylnonyl group, 1-methylheptadecyl group, 1-ethylhexadecyl group, 1-propylpentadecyl group, 1-butyltetradecyl group, 1-
Pentyl tridecyl group, 1-hexyldecyl group, 1-
Heptylundecyl group, 1-octyldecyl group, tert-
Butyl group, tert-amyl group, 1,1-dimethylbutyl group,
1-ethyl-1-methylpropyl group, 1,1-dimethylpentyl group, 1-ethyl-1-methylbutyl group, 1,1-diethylpropyl group, 1,1-dimethylhexyl group, 1-ethyl-1-methyl Pentyl group, 1,1-diethylbutyl group, 1,1-dimethylheptyl group, 1-ethyl-1-methylhexyl group, 1,1-diethylpentyl group, 1,1-dimethyloctyl group, 1-ethyl-1 -Methylheptyl group, 1,
1-diethylhexyl group, 1,1-dimethylnonyl group, 1-
Ethyl-1-methyloctyl group, 1,1-diethylheptyl group, 1,1-dimethyldecyl group, 1-ethyl-1-methylnonyl group, 1,1-diethyloctyl group, 1,1-dimethylundecyl group, 1-ethyl-1-methyldecyl group, 1,1
-Diethylnonyl group, 1,1-dimethyldodecyl group, 1-
Ethyl-1-methylundecyl group, 1,1-diethyldecyl group, 1,1-dimethyltridecyl group, 1-ethyl-1-
Methyldodecyl group, 1,1-diethylundecyl group, 1,1-
Dimethyl tetradecyl group, 1-ethyl-1-methyl tridecyl group, 1,1-diethyl dodecyl group, 1,1-dimethyl pentadecyl group, 1-ethyl-1-methyl tetradecyl group, 1,1-diethyl tri group Decyl group, 1,1-dimethylhexadecyl group, 1-ethyl-1-methylpentadecyl group, 1,
Examples thereof include 1-diethyltetradecyl group.

Further, in the present invention, as preferable examples of the alkylene group represented by R ₁ and R ₂ of the naphthyl ether compound or the naphthol ester compound, specifically, for example,
Tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, detradecamethylene group, pentadecamethylene group , Hexadecamethylene group, heptadecamethylene group, octadecamethylene group, nonadecamethylene group, eicosamethylene group, 1-methyl group, trimethylene group, ethylethylene group, 1-methyltetramethylene group, 1-ethyltrimethylene group Group, 1-methylpentamethylene group, 1-ethyltetramethylene group, 1-methylhexamethylene group, 1-ethylpentamethylene group, 1-
Methylheptamethylene group, 1-ethylhexamethylene group, 1-methyloctamethylene group, 1-ethylheptamethylene group, 1-methylnonamethylene group, 1-ethyloctamethylene group, 1-methyldecamethylene group, 1-ethyl Nonamethylene group, 1-methylundecamethylene group, 1-
Ethyl decamethylene group, 1-methyl group, 1-dodecamethylene group, 1-ethylundecamethylene group, 1-methyltridecamethylene group, 1-ethyldodecamethylene group, 1-
Methyltetradecamethylene group, 1-ethyltridecamethylene group, 1-methylpentadecamethylene group, 1-ethyltetradecamethylene group, 1-methylhexadecamethylene group, 1-ethylpentadecamethylene group, 1-methyl group ,
1-heptadecamethylene group, 1-ethylhexadecamethylene group, 1,1-dimethylethylene group, 1,1-dimethyltrimethylene group, 1,1-dimethyltetramethylene group, 1,1-dimethylpentamethylene group, 1,1-dimethylhexamethylene group, 1,1-dimethylheptamethylene group, 1,1-dimethyloctamethylene group, 1,1-dimethylnonamethylene group, 1,1
-Dimethyldecamethylene group, 1,1-dimethylundecamethylene group, 1,1-dimethyldodecamethylene group, 1,1-dimethyltridecamethylene group, 1,1-dimethyltetradecamethylene group, 1,1-dimethyl Pentadecamethylene group, 1,1-
Examples thereof include a dimethylhexadecamethylene group.

As long as the structures of the naphthyl ether compound and the naphthol ester compound in the present invention are within the above ranges, the lubricating oil of the present invention may be a specific one compound or a mixture of two or more compounds. Absent. Further, a naphthyl ether compound and a naphthol ester compound can be mixed and used.

The synthesis method of the naphthyl ether compound and the naphthol ester compound used in the present invention is arbitrary, but the naphthol ester compound is usually obtained by an esterification reaction of naphthol with a carboxylic acid or a carboxylic acid derivative. For example, it can be obtained by reacting naphthol with carboxylic acid chloride at room temperature.

Of the naphthyl ether compounds, the alkyl naphthyl ether compounds are usually Williams (Williams
on) can be obtained by synthesis. That is, it is obtained by synthesizing sodium naphthoxide from naphthol and then reacting it with an alkyl halide under heating.

Of the naphthyl ether compounds, the alkylphenyl naphthyl ether compounds are usually Ullman (Ullman) compounds.
n) It can be obtained by reaction. That is, it is obtained by heating halogenated naphthalene in the presence of a catalyst such as copper, copper (I) oxide, copper (I) chloride, copper (I) iodide, or iron (III) chloride to react with alkylphenol. .

The synthetic lubricating oil containing at least a naphthyl ether compound or a naphthol ester compound as a main component according to the present invention has excellent properties such as oxidation stability as well as various properties required for ordinary lubricating oils alone. In the synthetic lubricating oil of the present invention, known lubricating oil additives which are usually used as required, for example, antioxidants, detergent dispersants, viscosity index improvers, pour point depressants, oiliness agents, wear resistance Agents, extreme pressure agents, corrosion inhibitors, metal deactivators, rust inhibitors, defoamers, emulsifiers, demulsifiers, bactericides, colorants and the like may be added. Details of these various additives are described, for example, in "Journal of the Lubricating Oil Society, Vol. 15, No. 6," or "Toshio Sakurai," Petroleum Product Additives "(Koushobo)". The total amount of the agents added is 10 wt% or less, preferably 5 wt% or less, particularly preferably 3 wt% or less, based on the total amount of the lubricating oil.

Further, the synthetic lubricating oil of the present invention may be mineral oil or a known synthetic lubricating oil, such as polybutene or α-olefin oligomer, if necessary, in a range that does not impair its high oxidative stability.
Synthetic lubricating oil such as alkylbenzene, alkylnaphthalene, diester compound, polyol ester compound, polyglycol, polyphenyl ether compound, tricresyl phosphate, silicone oil, perfluoroalkyl ether compound is less than 50 wt% based on the total amount of lubricating oil, preferably Can be mixed in an amount of 30 wt% or less, particularly preferably 20 wt% or less.

The synthetic lubricating oil containing at least a naphthyl ether compound or a naphthol ester compound as a main component according to the present invention is, for example, a diesel engine oil such as a gasoline engine oil, a land diesel engine oil or a marine diesel engine oil, an additive-free turbine oil, an additive turbine. Turbine oil such as oil, gas turbine oil, marine turbine oil, etc., automobile gear oil, industrial gear oil, gear oil such as automatic transmission oil, hydraulic oil, compressor oil, refrigerating machine oil, cutting oil, grinding oil, plastic working It can be used as metal working oil such as oil, heat treatment oil, electric discharge machining oil, sliding guide surface oil, bearing oil, etc.

[Examples] Hereinafter, the content of the present invention will be described more specifically with reference to Examples and Comparative Examples.

Example 1 1 mol of α-naphthol and 300 m ethanol in a flask
l was added and α-naphthol was stirred and dissolved, and then 300 ml of ethanol in which 1 mol of sodium hydroxide was dissolved was added dropwise at room temperature over 2 hours. After dropping, the mixture was stirred at room temperature for 1 hour, ethanol was distilled off, benzene (300 ml) was added to dissolve the precipitate, and 2-ethylhexanoyl chloride (150 g) was added.
Was added dropwise at room temperature over 2 hours. After the dropping, the mixture was further stirred at room temperature for 1 hour, the reaction mixture was neutralized with an aqueous sodium carbonate solution, washed with water, and distilled under reduced pressure to give a compound of the formula 180 g of the desired product represented by Boiling point is 184-189 ℃ / 6
It was mmHg.

In order to evaluate the performance of the obtained product, the following evaluation test was conducted, and the results are shown in Table 1.

[Viscosity] The kinematic viscosity at 40 ° C and 100 ° C was measured according to the kinematic viscosity test method for crude oil and petroleum products specified in JIS-K-2283.

[Oxidation test life] A rotary cylinder type oxidation test specified in JIS-K-2514-3.3 was performed. The oxidation performance was evaluated by the time required for the oxygen pressure to drop by 1.8 kg / cm ² .

Test temperature: 150 ° C. Oxygen pressure: 13 kg / cm ² Catalyst: Copper wire 1.60 mmφ Example 2 1 mol of α-naphthol and 300 m of ethanol in a flask.
l was added and α-naphthol was stirred and dissolved, and then 300 ml of ethanol in which 1 mol of sodium hydroxide was dissolved was added dropwise at room temperature over 1 hour. After the dropwise addition, 1 mol of octyl chloride was added dropwise over 1 hour, and the mixture was refluxed for 3 hours. After the reaction was completed, ethanol was distilled off, the reaction mixture was neutralized with sodium carbonate, washed with water, and distilled under reduced pressure.
formula 180 g of the desired product represented by Boiling point is 183-185 ℃ / 4
It was mmHg. The performance of the obtained product was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 In the same manner as in Example 2 except that β-naphthol was used instead of α-naphthol, the formula 140 g of the desired product represented by Boiling point is 184-187 ℃ / 7
It was mmHg. The performance of the obtained product was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Example 4 1 mol of α-promnaphthalene, 1.3 mol of p-sec-butylphenol, 0.5 mol of copper (I) oxide and 2 mol of γ-collidine were placed in a flask and heated and refluxed for 6 hours. After completion of the reaction, the mixture was cooled to room temperature, the reaction mixture was filtered, the filtrate was distilled under reduced pressure, 125 g of the desired product represented by Boiling point is 198-201 ℃ / 4
It was mmHg. The performance of the obtained product was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Examples 1 to 4 Average molecular weight 50 conventionally used as a synthetic lubricating oil
0 1-decene oligomer (Comparative Example 1), dinonyl adipate (Comparative Example 2), pentaerythritol tetracapryate (Comparative Example 3) and the total carbon number of alkyl groups
The oxidation stability of 12 to 24 dialkylbenzenes (Comparative Example 4) was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

As is clear from the results of the oxidation test life in Table 1, the synthetic lubricating oil comprising the naphthyl ether compound or the naphthol ester compound according to the present invention exhibits very high oxidation stability at high temperature. On the other hand, compounds such as poly α-olefins, diester compounds, polyester compounds, and alkylbenzenes, which are said to be more excellent in oxidative stability than the conventional ones, show that the oxidation test life is significantly inferior to that of the synthetic lubricating oil of the present invention. .

[Effects of the Invention] As described above, the synthetic lubricating oil of the present invention containing at least a naphthyl ether compound or a naphthol ester compound as a main component has high oxidative stability that cannot be achieved by conventionally known synthetic lubricating oils. Is.

[Brief description of drawings]

FIG. 1 is a diagram showing a ¹ H NMR spectrum of the o-sec butylphenyl-1-naphthyl ether compound of the present invention, FIG. 2 is a diagram showing a ¹³ C NMR spectrum of the compound, and FIG. It is a figure which shows the mass spectrum of the same compound.

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Claims (1)

[Claims] 1. A naphthyl ether compound represented by the following general formula (I): [In the formula, X ₁ represents an alkyl group having 1 to 20 carbon atoms, a phenyl group,
C7-C26 monoalkylphenyl group or general formula And (or R ₁ represents an alkylene group having 2 to 20 carbon atoms)] and / or a naphthol ester compound represented by the following general formula (II) [In the formula, X ₂ is an alkyl group having 1 to 20 carbon atoms, or (Wherein R ₂ represents an alkylene group having 1 to 20 carbon atoms, and n represents a number of 0 or 1)] as a main component.